zstd.c

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#include "config.h"
#include <stdio.h>
#include <zstd.h>
#include "private.h"
#include "mutt/lib.h"
#include "lib.h"
 
#define MIN_COMP_LEVEL 1  
#define MAX_COMP_LEVEL 22 
 
struct ZstdComprData
{
  void *buf;   
  short level; 
 
  ZSTD_CCtx *cctx; 
  ZSTD_DCtx *dctx; 
};
 
void zstd_cdata_free(struct ZstdComprData **ptr)
{
  if (!ptr || !*ptr)
    return;
 
  struct ZstdComprData *cdata = *ptr;
  FREE(&cdata->buf);
 
  FREE(ptr);
}
 
static struct ZstdComprData *zstd_cdata_new(void)
{
  return mutt_mem_calloc(1, sizeof(struct ZstdComprData));
}
 
static ComprHandle *compr_zstd_open(short level)
{
  struct ZstdComprData *cdata = zstd_cdata_new();
 
  cdata->buf = mutt_mem_calloc(1, ZSTD_compressBound(1024 * 128));
  cdata->cctx = ZSTD_createCCtx();
  cdata->dctx = ZSTD_createDCtx();
 
  if (!cdata->cctx || !cdata->dctx)
  {
    // LCOV_EXCL_START
    ZSTD_freeCCtx(cdata->cctx);
    ZSTD_freeDCtx(cdata->dctx);
    zstd_cdata_free(&cdata);
    return NULL;
    // LCOV_EXCL_STOP
  }
 
  if ((level < MIN_COMP_LEVEL) || (level > MAX_COMP_LEVEL))
  {
    mutt_debug(LL_DEBUG1, "The compression level for %s should be between %d and %d",
               compr_zstd_ops.name, MIN_COMP_LEVEL, MAX_COMP_LEVEL);
    level = MIN_COMP_LEVEL;
  }
 
  cdata->level = level;
 
  // Return an opaque pointer
  return (ComprHandle *) cdata;
}
 
static void *compr_zstd_compress(ComprHandle *handle, const char *data,
                                 size_t dlen, size_t *clen)
{
  if (!handle)
    return NULL;
 
  // Decloak an opaque pointer
  struct ZstdComprData *cdata = handle;
 
  size_t len = ZSTD_compressBound(dlen);
  mutt_mem_realloc(&cdata->buf, len);
 
  size_t rc = ZSTD_compressCCtx(cdata->cctx, cdata->buf, len, data, dlen, cdata->level);
  if (ZSTD_isError(rc))
    return NULL; // LCOV_EXCL_LINE
 
  *clen = rc;
 
  return cdata->buf;
}
 
static void *compr_zstd_decompress(ComprHandle *handle, const char *cbuf, size_t clen)
{
  if (!handle)
    return NULL;
 
  // Decloak an opaque pointer
  struct ZstdComprData *cdata = handle;
 
  unsigned long long len = ZSTD_getFrameContentSize(cbuf, clen);
  if (len == ZSTD_CONTENTSIZE_UNKNOWN)
    return NULL; // LCOV_EXCL_LINE
  else if (len == ZSTD_CONTENTSIZE_ERROR)
    return NULL;
  else if (len == 0)
    return NULL; // LCOV_EXCL_LINE
  mutt_mem_realloc(&cdata->buf, len);
 
  size_t rc = ZSTD_decompressDCtx(cdata->dctx, cdata->buf, len, cbuf, clen);
  if (ZSTD_isError(rc))
    return NULL; // LCOV_EXCL_LINE
 
  return cdata->buf;
}
 
static void compr_zstd_close(ComprHandle **ptr)
{
  if (!ptr || !*ptr)
    return;
 
  // Decloak an opaque pointer
  struct ZstdComprData *cdata = *ptr;
 
  if (cdata->cctx)
    ZSTD_freeCCtx(cdata->cctx);
 
  if (cdata->dctx)
    ZSTD_freeDCtx(cdata->dctx);
 
  zstd_cdata_free((struct ZstdComprData **) ptr);
}
 
COMPRESS_OPS(zstd, MIN_COMP_LEVEL, MAX_COMP_LEVEL)